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[Solved] Replacing Idler Arm


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Does a vehicle need to be jacked up and set on stands to replace an idler arm, or can you do it if it's accessible with all 4 tires on the ground? I'm going to try to replace the idler arm in my 1979 Catalina soon and I've noticed I can get at the arm's bolts with the car sitting on all four wheels. 

7 Answers
Topic starter

That center link ball joint stud still won't budge out of that idler arm. I swapped the fork for a smaller Pitman arm puller this morning. That pulled it up maybe 1/8", and then the feet of the tool started widening and riding up the arm, haha. I honestly can't tell if the ball joint itself started to pull out or if the arm moved ever so slightly.

I tried heat and banging on it, even rocked the steering wheel back and forth with the power steering assist. No luck. Will a heavier duty tie puller get this thing out? I was considering cutting it out with my grinder, but that would be a risky, quite delicate task.

You may need to get some real heat on there, not propane but oxy-acetylene along with a heavier puller. If that's the original idler then those parts have been together for over 40 years and it's going to take a lot of persuasion to get them apart.

I got it off this morning in about 10 minutes with a pretty stout tie-rod end puller. The popping sound of the idler coming off startled me. Haha. Should I get the alignment re-checked? There is a difference in the steering. There's less of a feeling of "memory" like it wants to keep turning right slightly when I turn back straight.

Nice! Sometimes you just need a "bigger hammer". Yes, you should get an alignment any time front end parts are changed. Before doing that you might want to check for wear and looseness in other front end components (ball joints, control arm bushings, pitman arm) since a proper alignment cannot be done if there are loose parts. Also check for wear in the steering box. That doesn't affect alignment but does affect overall steering feel.


No need to raise it if you have enough room to get at everything.



Topic starter

I was up underneath the car a few minutes ago comparing the new arm with the arm in the car, as well as the shop manual. There are a couple differences, mainly that the new arm seems to be rotated 90 degrees from how it should be when it's installed in the car. How difficult are these arms to rotate around their bushings? I can't rotate it holding it in my hands, but I have not tried to bolt it to the frame for leverage, yet. 

The other difference is the frame mount on the new one is not a separate piece that needs to be set a certain distance before installation, the hole distances match the specifications within the tolerances. GM must have simplified these, as even the new "OEM" AC Delco arms do not appear to have this adjustment anymore. 

When new these are pretty tight. You should be able to move the arm with the mount in a bench vise or bolted to the car. Is the adjustable one you're replacing OEM? It sounds more like an aftermarket part that can be adjusted to fit different applications.

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Here's the actual installation procedure from GM's 1978 dealer's service manual. The car's arm matches this diagram, so it's probably the original. It looks like they made the idler arm itself separate from the support back then, and in the last 43 years, they went typical GM and made it all one piece to be cheap. This arm also fits several other GM vehicles. 


Idler Arm Instructions

Sounds like GM! Is the new OEM part "Hecho en China"?

Sure is, just like the brake parts from a few months ago. The arm shouldn't be too difficult to get off the car (knocking on wood, haha) it looks like at least the front end was undercoated at some point, or it's just covered in accumulated grease. The nuts are relatively rust-free underneath, so hopefully they won't put up a fight to come off, haha. We'll find out.

Hecho en Hell!


are you replacing everything but the hub caps? Nerd  

Topic starter

I borrowed a tie rod end puller from the store this morning that was more cupped and reinforced than the small pitman arm puller I used yesterday. It popped that stubborn idler arm right out and I got the new one in, in little more than 20 minutes. There's much less steering "memory" when turning right and back straight.


Should I pay to have the alignment rechecked after I put that new arm in? I put it in with all 4 wheels on the ground, so the wheel really couldn't move from where it was set with the old arm.